Concrete U-channels in the application of water-saving irrigation

Abstract The structure of concrete U-channel characteristics of a concrete U-channel features and benefits of investment and construction in order to promote concrete U-channel Application.

Keywords concrete U-channel; water-saving irrigation; Application

In order to solve tensions in northern water, local government has increased investment in agricultural water-saving irrigation projects, promotion of advanced water-saving irrigation Technology. From the irrigation renovation, comprehensive agricultural development, World Bank, poverty alleviation projects to raise funds through various channels, plus construction of a large anti-seepage, irrigation water to ease the conflict.

Concrete U-channel is now recognized as effective with impermeable, water capacity, resistance to frost, saving advantages of channels covering a water-saving irrigation facilities [1], but very difficult artificial construction, the quality can not be guaranteed. Water technical staff in recent years after many years of practice and promotion of concrete U-channels, the level of mechanical construction has been further improved, especially impervious concrete U-channel construction machinery industry sets the Research and promotion of development, so that concrete U-channel construction speed, and the concrete of high quality, suitable for China, promoting the use of easy.

A concrete U-channels, the structural characteristics of concrete
Concrete U-channel anti-arch structure, frost and strong and difficult to destroy. U shape canal end of the arc to 152 ~ 156 �� angle is appropriate, both sides of the extrovert 12 ~ 14 ��, drainage depth and diameter of a circle : 1, concrete thickness of 4 ~ 10cm. Special-area slope angle can be adjusted, such as the development of irrigation in Xinjiang desert, concrete U-channel to 18 �� appropriate camber; Hercynian alpine region of Qinghai Province, it would take appropriate increase in concrete lining thickness, to increase the ability of anti-freezing [2].

Characteristics of concrete U-channel 2
Impervious concrete U-channel 2.1 effective
Concrete U-channel of high integrity, anti-seepage effect, fighting the following canal lining the channel utilization factor of about 0.99, the soil drains without lining the utilization factor has not yet reached 0.8. A 133.3hm2 the lateral canal irrigated area, average annual shrub land 266.7hm2, in water about 40 million m3, without lining the channel will leak 80,000 m3 of water. 5 3.333 million hm2 of irrigated farmland, water shortages serious than 2 6667000 hm2, there are more than 20 lateral canal million in each of the following channel seepage fighting more than 100 million m3 of irrigation water, the irrigation water can leak out to over 6.667 million hm2 times, some areas will result in leakage of water or soil salinization of groundwater rise and other hazards .

Water saving irrigation has caused water sector at all levels of leadership and attention from all aspects of raising funds to increase investment in water projects, construction of concrete in the U-seepage irrigation channels, to promote advanced irrigation Technology, enhance irrigation water management, improve the efficiency of irrigation water, agricultural water sector at all levels made great efforts to water-saving irrigation and received good results. Fufeng County of Shaanxi Province, such as the village of concrete and construction of U-Village, channel lining is completed, the land of farmers pouring 666.67m2 5 yuan to less water out of the village land over 133.33hm2 province each year will be able to pour water to 2 million yuan, to achieve "a reduction of five provinces and two additional" objective, namely, the five provinces: saving water, saving time, the provincial labor , money and land; two growth: output, income; a few: the masses less water disputes. reposted elsewhere in the Research Papers Download http://www.hi138.com 2.2 Concrete U-canal ability
Smooth surface of concrete U-channels, roughness is small, good flow, water capacity, channel flow rate 1.2m / s, while the same slope of trapezoidal earth channel is only 0.6m / s. trapezoidal earth channel roughness values 0.025, concrete U-channel roughness value of around 0.013, so that the flow rate to accelerate, increase transport capacity. If Huangzhong County, Qinghai Province, Xining, united by concrete U-channel irrigation channels, water diversion channel to prevent a number of sediment deposition problems. Mutual Fifty East County area drains, channels weeds, poor water, the use of concrete U-channel resolves the problem of canal [3].

2.3 Concrete U-channel saving labor, material saving, saving channels covering
Concrete U-channel flow speed, small cross section. By mechanical construction of high efficiency, speed, quality, per capita per day may be lining concrete U-channel 10 ~ 20m, complete the concrete volume 1.5 ~ 2.0m3. Concrete U- channel saving materials, such as building 1km D60U type channels with a concrete volume of 96m3, while the construction of a trapezoidal channel of the same amount of water had to be concrete 132m3, construction of concrete U-channels than concrete trapezoidal channel can save about 1 million investment, can reduce the channel area of 0.2 hm2 above. concrete U-channel long life, in Qinghai Haixi Delingha Xiangride the construction of irrigation in 1999, concrete U-channel has run well without the phenomenon of frost damage, while the construction of the trapezoidal channel is not to 10 years to some or all of the damage.

3 concrete U-channel construction investment and benefit of
U-channel construction of concrete Application according to local investigation and analysis of an area 133.3hm2 places put together, a total fighting, agriculture, wool channel about 10km a year filling in about 266.7hm2, 40 million of the total water m3, 10km canal lining required after investment 20 million, of which material costs, transportation costs about 15 million labor costs 5 million. canal lining to reduce seepage of water after the 80,000 year m3, worth 2 million, not counting the increase in value, only the water savings 10 years to recover the investment, and service life of concrete U-channels, more than 30 years, but also reduce the channel area of over 2hm2. from the very favorable terms of investment returns, but more importantly, saving the water, poured more than land, increased income of farmers, greater social benefits.

4 concrete U-channel construction of the promotion of anti-seepage
Concrete U-channel is an important water-saving irrigation seepage in the project is to improve the effectiveness of existing water conservancy projects, improve qu shui utilization coefficient, water conservation and an important way to faster aging [4]. Concrete U-channel machine construction Technology by Ministry of Water Resources, Department of Water Resources in Qinghai Province and water management at all levels of leadership support. Qinghai Province Water Authority leadership attaches great importance to the project's Research and extension, and actively raise funds for renovation to increase irrigation canal seepage works inputs, irrigation farmers to reduce the burden of water to ease the contradiction between agricultural irrigation water irrigation has played a significant benefit.

5 References
[1] Yang. Mizoguchi of U-channel areas in the Application of [J]. Ningxia Science and Technology, 2002 (6) :56-55.

[2] Wu Guijiang. On the U-channel seepage control [J]. Science and Technology Information, 2007 (25): 274,276.

[3] Victor OK Li. Technique of canal seepage control project in China [J]. Seepage Technology, 2000 (1) :1-4, 16.

[4] Xuejun, FEI Liang-jun, ARID AREAS. U-type mechanism and freezing canal seepage technique [J]. Agricultural Research, 2006 (3) :194-199.

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